Gerber returned to the NHL for the 2005–06 season, and it was a successful one for Gerber, who won 38 games and helped earn Carolina their third division championship. Gerber entered the 2006 Stanley Cup playoffs as the Hurricanes' starting goaltender, but he struggled in the team's opening series and was replaced by rookie Cam Ward, who had been his back-up for most of the season. Ward went on to backstop the team to its first Stanley Cup championship as the Hurricanes defeated the Edmonton Oilers in seven games in the finals.[3] Gerber, who did earn 1 of Carolina's 16 playoff wins, became the second Swiss player in NHL history to win a Cup. David Aebischer, also a goaltender, was the first in 2001 with the Colorado Avalanche.[4]

On 1 July 2006, Gerber signed as a free agent with the Ottawa Senators.[5] He struggled throughout the season and was replaced as starting goaltender by Ray Emery. That season, Emery led the Senators to their first appearance in the Stanley Cup finals, where they would lose to Gerber's former team, the Anaheim Ducks. It was Gerber's third appearance in the Stanley Cup finals in five years.[6] Gerber began the 2007–08 season as the Senators' starter when Emery was sidelined after off-season wrist surgery. His play was inconsistent and Emery resumed the starting job once he was healthy again. However, after the team suffered a rapid decline in the standings and head coach John Paddock was fired and replaced by general manager Bryan Murray, Murray declared Gerber as the starting goaltender for the remainder of the season. Gerber entered the 2008–09 season in that role, but his uneven play continued and he was eventually supplanted by the newly signed Alex Auld. On 22 January 2009, Gerber was placed on waivers after having been sent down to the Senators American Hockey League (AHL) affiliate, the Binghamton Senators.[7]

Gerber sporting his all-black "Darth Gerber" mask with the Senators.

On 4 March 2009, Gerber was claimed off waivers by the Toronto Maple Leafs to replace goalie Vesa Toskala, who was scheduled for season-ending surgery.[8] During a game on 24 March against the Washington Capitals, Gerber was assessed a game-misconduct and immediately suspended for three games for an incident with the on-ice officials, during which Gerber was arguing a call and proceeded to make contact with referee Mike Leggo and a linesman who was attempting to restrain him.[9]

During the off-season, Gerber signed a deal with Atlant Moscow of the Kontinental Hockey League, coincidentally the same team that fellow former-Senators goaltender Ray Emery played for the previous season before returning to the NHL in 2009.[10] On 13 December 2009, while playing for Atlant, Gerber suffered an apparent fracture of the 4th vertebrae when an opposing forward slid into him. Gerber's neck injury was initially thought to be a compression fracture of a cervical vertebra, and it was believed that he would miss upwards of 6 months.[11] However, after more comprehensive testing the following day no fractures were found and it was diagnosed as a spinal contusion; he would only be sidelined for a few weeks.[12]

On 6 August 2010, Gerber signed a one-year contract with the Edmonton Oilers.[13] He was assigned to the team's AHL affiliate, the Oklahoma City Barons. He was recalled on 18 November after Oilers' goaltender Nikolai Khabibulin was placed on injured reserve.[14] Gerber made his first start for the Oilers on 25 November, picking up a 3-2 victory over the visiting Colorado Avalanche. He stopped 35 of 37 shots and drew an assist on the game-winning goal scored by Taylor Hall.[15] Gerber started one more game, a 4-1 victory at Ottawa against his former team, before Khabibulin was re-activated and Gerber was returned to the Barons. Gerber was again re-called in late February after another injury to Khabibulin. Picking up where he left off in late November, Gerber stopped 34 shots in a 2-1 shootout win over the Nashville Predators on 1 March, improving to a perfect 3-0 with Edmonton.[16]

On 12 July 2011, Gerber signed a one-year contract with the Växjö Lakers of the Elitserien (SEL).[17] Playing 42 games, he ended fifth in the save percentage league for the 2011–12 season with .928, and seventh in GAA with a 2.18 GAA. The Lakers failed to reach the playoffs. For the 2012–13 season he signed with the SEL team Rögle BK.[18] After a solitary season with Rogle, Gerber returned to Switzerland in signing a two-year contract with the Kloten Flyers.

To start the 2007–08 season, Gerber wore an all-black mask while his other mask was being painted; he played so well wearing the black mask that he decided not to replace it, wearing it for the remainder of the season. Fans endearingly called him "Darth Gerber". In response Gerber tried out a new Darth Vader inspired mask design to begin the 2008–09 season when he was still a member of the Senators.[19] The mask was worn by Gerber during the first few games with Toronto before he switched to a new one paying homage to old masks of the Toronto Maple Leafs of the past.

Gerber has been a mainstay on the Swiss national team, having represented his country in eight IIHF World Championships and two Winter Olympics since 2000. At the 2006 Winter Olympics, Gerber made 49 saves to shutout a heavily favored Team Canada 2-0 in one of the biggest upsets in modern Olympic hockey history. That victory is regarded as one of the greatest accomplishments in Swiss hockey.[20] Gerber has appeared in 40 games at the World Championships. Switzerland failed to medal in any of these tournaments, their highest finish being 5th in 2010, though their play has seen their IIHF World Rank increase from 9th in 2003 to 7th in 2010.